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SEGMENT INFORMATION - Schedule of Long-lived Assets and Net Sales By Geography (Details) - USD ($) $ in Thousands | 12 Months Ended
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Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |
Long-lived assets | $ 750,946 | $ 832,749 | $ 679,788
Net sales | 2,850,378 | 3,202,053 | 3,518,761
United States |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |
Long-lived assets | 681,948 | 756,108 | 612,066
Net sales | 2,501,481 | 2,817,844 | 3,150,143
Other Americas |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |
Long-lived assets | 8,253 | 9,168 | 8,655
Net sales | 80,380 | 92,361 | 94,064
Europe |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |
Long-lived assets | 53,300 | 55,907 | 52,498
Net sales | 220,803 | 245,764 | 228,885
Asia-Pacific |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |
Long-lived assets | 7,445 | 11,566 | 6,569
Net sales | $ 47,714 | $ 46,084 | $ 45,669

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